The present invention relates to a vertebral osteosynthesis equipment.
To treat the degeneration of one or more vertebral joints, it is known to use vertebral osteosynthesis equipment comprising anchoring members for anchoring to the vertebrae (pedicle screws and/or laminar hooks), connecting bars, connecting parts for connecting said bars to said anchoring members, and tightening nuts for tightening said connecting parts relative to said bars and anchoring members. As an example, patent application publication no. WO 98/55038 describes such an equipment.
In general, the existing equipment does not always appear to be well-suited to treating a short vertebral column segment, i.e., resolving a degeneration at one or two vertebral joints. In particular, they are relatively complicated and time-consuming to implant, which noticeably extends the procedure time.
Such an equipment may comprise at least one connecting part of the so-called “side loading” type, like those described in the aforementioned patent application publication no. WO 98/55038, i.e., in which the duct for engaging the connecting bar is laterally offset relative to a duct allowing the part to be mounted on a proximal pin comprised by the associated anchoring member. An equipment of this type has the drawback of causing, particularly when the connecting bar is short, the risk of one or more connecting parts escaping from that bar.
Furthermore, this type of equipment has the drawback of not ruling out pivoting of the connecting bar relative to the anchoring members during tightening of the nuts, occurring even more when that bar is short and curved. This may result in defective angular positioning of the bar, leading to an imperfect or even defective correction of the treated segment, and therefore involving loosening of the nuts and repositioning of the bar.
A vertebral osteosynthesis equipment also comprises at least one connecting part of the so-called “top loading” or “tulip” type, i.e., forming an engagement duct of the connecting bar whose axis is secant to the axis of the vertebral anchoring screw, said duct being closed, after implantation of the connecting bar thereon, by a threaded stopper screwed into the “tulip”. This type of equipment has the drawback of making it possible for the connecting bar to pivot as cited above, which occurs even more when that bar is short and curved. The threaded stoppers can be difficult to place, in particular because the connecting bar may not always be completely engaged in the ducts formed by the “tulips”, and it is then necessary to use an instrument to push the connecting bar into those duct so that it is possible to place the stoppers. Furthermore, such stoppers have small sizes and may undergo a deterioration of their thread when they are placed, problem known as “cross threading”.
The present invention aims to provide a vertebral osteosynthesis equipment resolving all of these drawbacks.
Furthermore, patent application publication no. U.S. 2008/312692 A1 describes a vertebral osteosynthesis equipment comprising at least one connecting bar, at least two anchoring members and at least one connecting part for connecting the connecting bar to the anchoring members. The connecting part comprises an engagement duct of the bar that is laterally offset relative to an assembly duct on the corresponding anchoring member. In this equipment, the part of the connecting bar designed to be engaged in said engagement duct is smooth, which does not make it possible to resolve the aforementioned drawback of the risk of one or more connecting parts escaping outside the bar, particularly when the connecting bar is short.
The main aim of the invention is therefore to provide simple and easy-to-place equipment that is particularly well-suited to treating a short vertebral column segment.
Another aim of the invention is to provide an equipment in which the risk of a connecting part of the so-called “side loading” type escaping outside the connecting bar is eliminated.
An additional aim of the invention is to provide an equipment in which the risk of pivoting of the connecting bar relative to the connecting parts is eliminated.
Still another aim of the invention is to provide an equipment in which the assembly of the connecting bar to the anchoring members is done simply and quickly.